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pgsql: Silence uninitialized-value warnings in compareJsonbContainers() 7+ messages / 1 participants [nested] [flat]
* pgsql: Silence uninitialized-value warnings in compareJsonbContainers() @ 2025-07-15 22:11 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 7+ messages in thread From: Tom Lane @ 2025-07-15 22:11 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Silence uninitialized-value warnings in compareJsonbContainers(). Because not every path through JsonbIteratorNext() sets val->type, some compilers complain that compareJsonbContainers() is comparing possibly-uninitialized values. The paths that don't set it return WJB_DONE, WJB_END_ARRAY, or WJB_END_OBJECT, so it's clear by manual inspection that the "(ra == rb)" code path is safe, and indeed we aren't seeing warnings about that. But the (ra != rb) case is much less obviously safe. In Assert-enabled builds it seems that the asserts rejecting WJB_END_ARRAY and WJB_END_OBJECT persuade gcc 15.x not to warn, which makes little sense because it's impossible to believe that the compiler can prove of its own accord that ra/rb aren't WJB_DONE here. (In fact they never will be, so the code isn't wrong, but why is there no warning?) Without Asserts, the appearance of warnings is quite unsurprising. We discussed fixing this by converting those two Asserts into pg_assume, but that seems not very satisfactory when it's so unclear why the compiler is or isn't warning: the warning could easily reappear with some other compiler version. Let's fix it in a less magical, more future-proof way by changing JsonbIteratorNext() so that it always does set val->type. The cost of that should be pretty negligible, and it makes the function's API spec less squishy. Reported-by: Erik Rijkers <er@xs4all.nl> Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/988bf1bc-3f1f-99f3-bf98-222f1cd9dc5e@xs4all.nl Discussion: https://postgr.es/m/0c623e8a204187b87b4736792398eaf1@postgrespro.ru Backpatch-through: 13 Branch ------ REL_15_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/f32e456414601a6cbf48eb33560f5074fa0a2d4b Modified Files -------------- src/backend/utils/adt/jsonb_util.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) ^ permalink raw reply [nested|flat] 7+ messages in thread
* pgsql: Silence uninitialized-value warnings in compareJsonbContainers() @ 2025-07-15 22:11 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 7+ messages in thread From: Tom Lane @ 2025-07-15 22:11 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Silence uninitialized-value warnings in compareJsonbContainers(). Because not every path through JsonbIteratorNext() sets val->type, some compilers complain that compareJsonbContainers() is comparing possibly-uninitialized values. The paths that don't set it return WJB_DONE, WJB_END_ARRAY, or WJB_END_OBJECT, so it's clear by manual inspection that the "(ra == rb)" code path is safe, and indeed we aren't seeing warnings about that. But the (ra != rb) case is much less obviously safe. In Assert-enabled builds it seems that the asserts rejecting WJB_END_ARRAY and WJB_END_OBJECT persuade gcc 15.x not to warn, which makes little sense because it's impossible to believe that the compiler can prove of its own accord that ra/rb aren't WJB_DONE here. (In fact they never will be, so the code isn't wrong, but why is there no warning?) Without Asserts, the appearance of warnings is quite unsurprising. We discussed fixing this by converting those two Asserts into pg_assume, but that seems not very satisfactory when it's so unclear why the compiler is or isn't warning: the warning could easily reappear with some other compiler version. Let's fix it in a less magical, more future-proof way by changing JsonbIteratorNext() so that it always does set val->type. The cost of that should be pretty negligible, and it makes the function's API spec less squishy. Reported-by: Erik Rijkers <er@xs4all.nl> Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/988bf1bc-3f1f-99f3-bf98-222f1cd9dc5e@xs4all.nl Discussion: https://postgr.es/m/0c623e8a204187b87b4736792398eaf1@postgrespro.ru Backpatch-through: 13 Branch ------ REL_18_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/0b6dfce0ce4dec2ddbf63e8d02f932b237a9f8c3 Modified Files -------------- src/backend/utils/adt/jsonb_util.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) ^ permalink raw reply [nested|flat] 7+ messages in thread
* pgsql: Silence uninitialized-value warnings in compareJsonbContainers() @ 2025-07-15 22:11 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 7+ messages in thread From: Tom Lane @ 2025-07-15 22:11 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Silence uninitialized-value warnings in compareJsonbContainers(). Because not every path through JsonbIteratorNext() sets val->type, some compilers complain that compareJsonbContainers() is comparing possibly-uninitialized values. The paths that don't set it return WJB_DONE, WJB_END_ARRAY, or WJB_END_OBJECT, so it's clear by manual inspection that the "(ra == rb)" code path is safe, and indeed we aren't seeing warnings about that. But the (ra != rb) case is much less obviously safe. In Assert-enabled builds it seems that the asserts rejecting WJB_END_ARRAY and WJB_END_OBJECT persuade gcc 15.x not to warn, which makes little sense because it's impossible to believe that the compiler can prove of its own accord that ra/rb aren't WJB_DONE here. (In fact they never will be, so the code isn't wrong, but why is there no warning?) Without Asserts, the appearance of warnings is quite unsurprising. We discussed fixing this by converting those two Asserts into pg_assume, but that seems not very satisfactory when it's so unclear why the compiler is or isn't warning: the warning could easily reappear with some other compiler version. Let's fix it in a less magical, more future-proof way by changing JsonbIteratorNext() so that it always does set val->type. The cost of that should be pretty negligible, and it makes the function's API spec less squishy. Reported-by: Erik Rijkers <er@xs4all.nl> Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/988bf1bc-3f1f-99f3-bf98-222f1cd9dc5e@xs4all.nl Discussion: https://postgr.es/m/0c623e8a204187b87b4736792398eaf1@postgrespro.ru Backpatch-through: 13 Branch ------ REL_16_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/5db55e13f2109c578f6fe0fce49574d801eef739 Modified Files -------------- src/backend/utils/adt/jsonb_util.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) ^ permalink raw reply [nested|flat] 7+ messages in thread
* pgsql: Silence uninitialized-value warnings in compareJsonbContainers() @ 2025-07-15 22:11 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 7+ messages in thread From: Tom Lane @ 2025-07-15 22:11 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Silence uninitialized-value warnings in compareJsonbContainers(). Because not every path through JsonbIteratorNext() sets val->type, some compilers complain that compareJsonbContainers() is comparing possibly-uninitialized values. The paths that don't set it return WJB_DONE, WJB_END_ARRAY, or WJB_END_OBJECT, so it's clear by manual inspection that the "(ra == rb)" code path is safe, and indeed we aren't seeing warnings about that. But the (ra != rb) case is much less obviously safe. In Assert-enabled builds it seems that the asserts rejecting WJB_END_ARRAY and WJB_END_OBJECT persuade gcc 15.x not to warn, which makes little sense because it's impossible to believe that the compiler can prove of its own accord that ra/rb aren't WJB_DONE here. (In fact they never will be, so the code isn't wrong, but why is there no warning?) Without Asserts, the appearance of warnings is quite unsurprising. We discussed fixing this by converting those two Asserts into pg_assume, but that seems not very satisfactory when it's so unclear why the compiler is or isn't warning: the warning could easily reappear with some other compiler version. Let's fix it in a less magical, more future-proof way by changing JsonbIteratorNext() so that it always does set val->type. The cost of that should be pretty negligible, and it makes the function's API spec less squishy. Reported-by: Erik Rijkers <er@xs4all.nl> Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/988bf1bc-3f1f-99f3-bf98-222f1cd9dc5e@xs4all.nl Discussion: https://postgr.es/m/0c623e8a204187b87b4736792398eaf1@postgrespro.ru Backpatch-through: 13 Branch ------ REL_14_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/8254b7e33be9cebe99286d99940fbe0dde79b970 Modified Files -------------- src/backend/utils/adt/jsonb_util.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) ^ permalink raw reply [nested|flat] 7+ messages in thread
* pgsql: Silence uninitialized-value warnings in compareJsonbContainers() @ 2025-07-15 22:11 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 7+ messages in thread From: Tom Lane @ 2025-07-15 22:11 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Silence uninitialized-value warnings in compareJsonbContainers(). Because not every path through JsonbIteratorNext() sets val->type, some compilers complain that compareJsonbContainers() is comparing possibly-uninitialized values. The paths that don't set it return WJB_DONE, WJB_END_ARRAY, or WJB_END_OBJECT, so it's clear by manual inspection that the "(ra == rb)" code path is safe, and indeed we aren't seeing warnings about that. But the (ra != rb) case is much less obviously safe. In Assert-enabled builds it seems that the asserts rejecting WJB_END_ARRAY and WJB_END_OBJECT persuade gcc 15.x not to warn, which makes little sense because it's impossible to believe that the compiler can prove of its own accord that ra/rb aren't WJB_DONE here. (In fact they never will be, so the code isn't wrong, but why is there no warning?) Without Asserts, the appearance of warnings is quite unsurprising. We discussed fixing this by converting those two Asserts into pg_assume, but that seems not very satisfactory when it's so unclear why the compiler is or isn't warning: the warning could easily reappear with some other compiler version. Let's fix it in a less magical, more future-proof way by changing JsonbIteratorNext() so that it always does set val->type. The cost of that should be pretty negligible, and it makes the function's API spec less squishy. Reported-by: Erik Rijkers <er@xs4all.nl> Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/988bf1bc-3f1f-99f3-bf98-222f1cd9dc5e@xs4all.nl Discussion: https://postgr.es/m/0c623e8a204187b87b4736792398eaf1@postgrespro.ru Backpatch-through: 13 Branch ------ REL_17_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/5a2139a9069043ae97088085b675b4099e520849 Modified Files -------------- src/backend/utils/adt/jsonb_util.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) ^ permalink raw reply [nested|flat] 7+ messages in thread
* pgsql: Silence uninitialized-value warnings in compareJsonbContainers() @ 2025-07-15 22:11 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 7+ messages in thread From: Tom Lane @ 2025-07-15 22:11 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Silence uninitialized-value warnings in compareJsonbContainers(). Because not every path through JsonbIteratorNext() sets val->type, some compilers complain that compareJsonbContainers() is comparing possibly-uninitialized values. The paths that don't set it return WJB_DONE, WJB_END_ARRAY, or WJB_END_OBJECT, so it's clear by manual inspection that the "(ra == rb)" code path is safe, and indeed we aren't seeing warnings about that. But the (ra != rb) case is much less obviously safe. In Assert-enabled builds it seems that the asserts rejecting WJB_END_ARRAY and WJB_END_OBJECT persuade gcc 15.x not to warn, which makes little sense because it's impossible to believe that the compiler can prove of its own accord that ra/rb aren't WJB_DONE here. (In fact they never will be, so the code isn't wrong, but why is there no warning?) Without Asserts, the appearance of warnings is quite unsurprising. We discussed fixing this by converting those two Asserts into pg_assume, but that seems not very satisfactory when it's so unclear why the compiler is or isn't warning: the warning could easily reappear with some other compiler version. Let's fix it in a less magical, more future-proof way by changing JsonbIteratorNext() so that it always does set val->type. The cost of that should be pretty negligible, and it makes the function's API spec less squishy. Reported-by: Erik Rijkers <er@xs4all.nl> Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/988bf1bc-3f1f-99f3-bf98-222f1cd9dc5e@xs4all.nl Discussion: https://postgr.es/m/0c623e8a204187b87b4736792398eaf1@postgrespro.ru Backpatch-through: 13 Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/aad1617b76aef034a27f2a52903702dc5435c422 Modified Files -------------- src/backend/utils/adt/jsonb_util.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) ^ permalink raw reply [nested|flat] 7+ messages in thread
* pgsql: Silence uninitialized-value warnings in compareJsonbContainers() @ 2025-07-15 22:11 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 7+ messages in thread From: Tom Lane @ 2025-07-15 22:11 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Silence uninitialized-value warnings in compareJsonbContainers(). Because not every path through JsonbIteratorNext() sets val->type, some compilers complain that compareJsonbContainers() is comparing possibly-uninitialized values. The paths that don't set it return WJB_DONE, WJB_END_ARRAY, or WJB_END_OBJECT, so it's clear by manual inspection that the "(ra == rb)" code path is safe, and indeed we aren't seeing warnings about that. But the (ra != rb) case is much less obviously safe. In Assert-enabled builds it seems that the asserts rejecting WJB_END_ARRAY and WJB_END_OBJECT persuade gcc 15.x not to warn, which makes little sense because it's impossible to believe that the compiler can prove of its own accord that ra/rb aren't WJB_DONE here. (In fact they never will be, so the code isn't wrong, but why is there no warning?) Without Asserts, the appearance of warnings is quite unsurprising. We discussed fixing this by converting those two Asserts into pg_assume, but that seems not very satisfactory when it's so unclear why the compiler is or isn't warning: the warning could easily reappear with some other compiler version. Let's fix it in a less magical, more future-proof way by changing JsonbIteratorNext() so that it always does set val->type. The cost of that should be pretty negligible, and it makes the function's API spec less squishy. Reported-by: Erik Rijkers <er@xs4all.nl> Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/988bf1bc-3f1f-99f3-bf98-222f1cd9dc5e@xs4all.nl Discussion: https://postgr.es/m/0c623e8a204187b87b4736792398eaf1@postgrespro.ru Backpatch-through: 13 Branch ------ REL_13_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/6c93bf735ce12d6973e0c359eeff648fa7d46652 Modified Files -------------- src/backend/utils/adt/jsonb_util.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) ^ permalink raw reply [nested|flat] 7+ messages in thread
end of thread, other threads:[~2025-07-15 22:11 UTC | newest] Thread overview: 7+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2025-07-15 22:11 pgsql: Silence uninitialized-value warnings in compareJsonbContainers() Tom Lane <tgl@sss.pgh.pa.us> 2025-07-15 22:11 pgsql: Silence uninitialized-value warnings in compareJsonbContainers() Tom Lane <tgl@sss.pgh.pa.us> 2025-07-15 22:11 pgsql: Silence uninitialized-value warnings in compareJsonbContainers() Tom Lane <tgl@sss.pgh.pa.us> 2025-07-15 22:11 pgsql: Silence uninitialized-value warnings in compareJsonbContainers() Tom Lane <tgl@sss.pgh.pa.us> 2025-07-15 22:11 pgsql: Silence uninitialized-value warnings in compareJsonbContainers() Tom Lane <tgl@sss.pgh.pa.us> 2025-07-15 22:11 pgsql: Silence uninitialized-value warnings in compareJsonbContainers() Tom Lane <tgl@sss.pgh.pa.us> 2025-07-15 22:11 pgsql: Silence uninitialized-value warnings in compareJsonbContainers() Tom Lane <tgl@sss.pgh.pa.us>
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